function varargout = fdellip(varargin)
%fdellip  Elliptic Module for filtdes.

%   Author: T. Krauss
%   Copyright 1988-2003 The MathWorks, Inc.
%   $Revision: 1.10.4.4 $

% Change this global to static when available:
%  following are common to several modules
global minOrdCheckbox bandpop order pbspecs sbspecs pbmeasures sbmeasures
global passframe stopframe passframe1 stopframe1
%  following static to fdellip
global f1 f2 f3 f4 Fp1 Fp2 Rp Rs 
global Fs1m Fs2m 
global order0 order1
global ax L1 L2 Lresp L3_1 L3_2
global Fs

switch varargin{1}
case 'init'

    filt = varargin{2};
    Fs = filt.Fs;
    [setOrderFlag_init, type_init, f_init, Rp_init, Rs_init, ...
      order_init, Fpass_init] = initSpecs(filt);

    [minOrdCheckbox bandpop order pbspecs sbspecs ...
         pbmeasures sbmeasures passframe stopframe ...
         passframe1 stopframe1 ax Lresp L1 L2 order1 ...
         L3_1 L3_2] = fdutil('commonObjects');
    order0 = order;
             
    co = get(0,'defaultaxescolororder');
    lo = get(0,'defaultaxeslinestyleorder');

    if ~strcmp(bandpop.userdata,'fdellip')
       % this module is not current
        bandpop.userdata = 'fdellip';
            
        minOrdCheckbox.callback = 'fdellip(''checkbox'')';
        bandpop.callback = 'fdellip(''newtype'')';         

        order0.callback = 'fdellip(''dirty'')';
                        
        set(ax,'title',xlate('Frequency Response'),...
              'xlabel',xlate('Frequency'),...
              'ylabel',xlate('Magnitude (dB)'),...
              'ylim',[-150 10],'xlim',[0 Fs/2],...
              'xlimbound',[0 Fs/2]);

        sethelp
        
        set(Lresp,'buttondownfcn','fdellip(''LrespDown'')')
                       
        set(L1,'buttondownfcn','fdellip(''L1down'')',...
               'buttonupfcn','fdellip(''L1up'')',...
               'color',co(min(2,size(co,1)),:))
        set(L2,'buttondownfcn','fdellip(''L2down'')',...
               'buttonupfcn','fdellip(''L2up'')',...
               'color',co(min(2,size(co,1)),:))
        set(L3_1,'xdata',Fpass_init([1 1]),...
                 'segmentdragcallback',{'fdellip(''L3_drag'',1)'},...
                 'buttondownfcn','fdellip(''L3_down'',1)',...
                 'buttonupfcn','fdellip(''L1up'')');
        set(L3_2,'xdata',Fpass_init([end end]),...
                 'segmentdragcallback',{'fdellip(''L3_drag'',2)'},...
                 'buttondownfcn','fdellip(''L3_down'',2)',...
                 'buttonupfcn','fdellip(''L1up'')');
        Rp = pbspecs(3);
        set(Rp,'value',Rp_init,'label','Rp')
        Rs = sbspecs(3);
        set(Rs,'value',Rs_init,'label','Rs')
        set(Rp,'callback','fdellip(''Rpchange'')')
        set(Rs,'callback','fdellip(''Rschange'')')
        Fp1 = pbspecs(1);
        Fp2 = pbspecs(2);
        Fs1m = sbmeasures(1);
        Fs2m = sbmeasures(2);
        % fdutil('changeToEdit',pbmeasures(1:3))
        fdutil('changeToText',[Fs1m Fs2m])
    end    
    set(minOrdCheckbox,'visible','on','enable','on')
    set(Rp,'visible','on')
    set(Rs,'visible','on')
    set(sbspecs(1),'visible','on')
    set(Fs1m,'visible','on')
    set(pbmeasures(1),'visible','off')
    set(pbmeasures(2),'visible','off')
    set(pbmeasures(3),'visible','off')
    set(sbmeasures(3),'visible','off')
        
    fdellip('newfilt',setOrderFlag_init,type_init,f_init,Rp_init,...
               Rs_init,Fpass_init,order_init)
    
    [filt, errstr] = fdutil('callModuleApply',...
                               'fdellip',filt,'');
    varargout{1} = filt;
    varargout{2} = errstr;

case 'apply'    
    
    filt = varargin{2};
    msg = varargin{3};
    
    % DESIGN FILTER!!!!
    type = bandpop.value;
    setOrderFlag = ~minOrdCheckbox.value;
    if ~setOrderFlag     % estimate order
        [n,Fpass] = estimateOrder(type,Rp.value,Rs.value,Fs,...
                 f1.value,f2.value,f3.value,f4.value);
    else
        n = order.value;
        Fpass = Fp1.value * 2/Fs;
        if type > 2  % pass/stop
            Fpass(2) = Fp2.value * 2/Fs;
        end
    end
    
    % save specifications in specifications structure:
    specstruc.setOrderFlag = setOrderFlag;
    specstruc.type = type;
    if ~setOrderFlag
        f = getFrequencyValues(type,f1,f2,f3,f4,Fs);
        specstruc.f = f;
    else
        specstruc.f = [];  % place holder, will be defined by measureFilt
    end
    specstruc.Rp = Rp.value;
    specstruc.Rs = Rs.value;
    specstruc.Fpass = Fpass;
    if specstruc.type > 2     
    % ellip(N,...) returns a 2N order filter for bandpass and bandstop filter 
        specstruc.order = 2*n;
    else
        specstruc.order = n;
    end
                          
%     if ~setOrderFlag & isfield(filt.specs,'fdellip') & ...
%         isequal(specstruc.Fpass,filt.specs.fdellip.Fpass) ...
%         & isequal(specstruc.order,filt.specs.fdellip.order)
%         filt.specs.fdellip = specstruc;
%         varargout{1} = filt;
%         varargout{2} = '';
%         return
%     end

    if n>50
        [continueFlag,errstr] = fdutil('largeWarning',n,msg);
        if ~continueFlag
            varargout{1} = filt;
            varargout{2} = errstr;
            return
        end
    end
        
    % design filter:
    if type == 2
        [b,a] = ellip(n,specstruc.Rp,specstruc.Rs,Fpass,'high');
    elseif type == 4
        [b,a] = ellip(n,specstruc.Rp,specstruc.Rs,Fpass,'stop');
    else
        [b,a] = ellip(n,specstruc.Rp,specstruc.Rs,Fpass);
    end
        
    % compute frequency response:
    nfft = filtdes('nfft');
    [H,ff] = freqz(b,a,nfft,Fs);
    % avoid log of 0 at 0 and Fs/2:
    if H(1) == 0, H(1) = H(2); end
    if H(end) == 0, H(end) = H(end-1); end
    Hlog = 20*log10(abs(H(:)));
    set(Lresp,'xdata',ff,'ydata',Hlog);
    
    % make measurements:
    if ~ ((strcmp(msg,'motion') | strcmp(msg,'up')) & ~setOrderFlag ...
             & strcmp(get(order1,'visible'),'on') )  | ...
       (~setOrderFlag & (filt.specs.fdellip.type ~= type))
        objSetupFlag = 1;
    else
        objSetupFlag = 0;
    end
    
    specstruc = measureFilt(objSetupFlag,specstruc,Fs,order1,...
                  sbmeasures,Fs1m,Fs2m,ff,Hlog,L1,L2,ax);
                      
    if ~strcmp(msg,'motion')
        % if design is due to a drag operation, lines are already solid
        % so we can skip this step
        Lresp.linestyle = '-';
        L1.linestyle = '-';
        L2.linestyle = '-';
        set(L3_1,'linestyle','-')
        set(L3_2,'linestyle','-')
    end
    
    % alter filt fields:
    filt.tf.num = b;
    filt.tf.den = a;
    filt.specs.fdellip = specstruc;
    filt.zpk = [];  % clear out in case filtview has written these
    filt.ss = [];
    filt.sos = [];
    filt.type = 'design';

    varargout{1} = filt;
    varargout{2} = '';
        
case 'revert'
    filt = filtdes('filt');
    oldtype = filt.specs.fdellip.type;
    % need to restore filter type
    setOrderFlag = filt.specs.fdellip.setOrderFlag;
    oldSetOrderFlag = ~minOrdCheckbox.value;
    f = filt.specs.fdellip.f;
    Rpass = filt.specs.fdellip.Rp;
    Rstop = filt.specs.fdellip.Rs;
    Fpass = filt.specs.fdellip.Fpass;
    N = filt.specs.fdellip.order;
    fdellip('newfilt',setOrderFlag,oldtype,f,Rpass,Rstop,Fpass,N)

    specStruc = measureFilt(1,filt.specs.fdellip,Fs,order1,...
                  sbmeasures,Fs1m,Fs2m,Lresp.xdata,Lresp.ydata,L1,L2,ax);

    Lresp.linestyle = '-';
    L1.linestyle = '-';
    L2.linestyle = '-';
    set(L3_1,'linestyle','-')
    set(L3_2,'linestyle','-')
    
    for i=1:2
        set(sbmeasures(i),'enable','on')
    end
    set(order1,'enable','on')
    
case 'help'
    str = fdhelpstr('fdellip');
    varargout{1} = str{2};

case 'description'
    varargout{1} = 'Elliptic IIR';

case 'Fs'
% Sampling frequency has changed

%   The filter spec does not depend on the sampling frequency
    filt = varargin{2};
    varargout{1} = filt;
    
% update various lines and specifications:
    oldFs = varargin{3};
    Fs = filt.Fs;  % new Fs
    if minOrdCheckbox.value
        f1.value = f1.value*Fs/oldFs;
        f2.value = f2.value*Fs/oldFs;
        f3.value = f3.value*Fs/oldFs;
        f4.value = f4.value*Fs/oldFs;
        f1.range = f1.range*Fs/oldFs;
        f2.range = f2.range*Fs/oldFs;
        f3.range = f3.range*Fs/oldFs;
        f4.range = f4.range*Fs/oldFs;
    else
        Fp1.value = Fp1.value*Fs/oldFs;
        Fp2.value = Fp2.value*Fs/oldFs;
        Fp1.range = Fp1.range*Fs/oldFs;
        Fp2.range = Fp2.range*Fs/oldFs;
    end
    
    ax.xlimbound = [0 Fs/2];
    ax.xlim = ax.xlim*Fs/oldFs;
    ax.xlimpassband = ax.xlimpassband*Fs/oldFs;
    L1.xdata = L1.xdata*Fs/oldFs;
    L2.xdata = L2.xdata*Fs/oldFs;
    Lresp.xdata = Lresp.xdata*Fs/oldFs;
    L3_1.xdata = L3_1.xdata*Fs/oldFs;
    L3_2.xdata = L3_2.xdata*Fs/oldFs;
    
    Fs1m.value = Fs1m.value*Fs/oldFs;
    Fs2m.value = Fs2m.value*Fs/oldFs;
    
%---------------------------------------------------------------------
% -------- following cases are module specific --------- 
%---------------------------------------------------------------------

case 'dirty'
% fdellip('dirty')
% Callback of a spec ... to change appearance so user can
%  see that the specs and the currently designed filter
%  don't match
    if Lresp.linestyle ~= ':'
        Lresp.linestyle = ':';
        L1.linestyle = ':';
        L2.linestyle = ':';
        L3_1.linestyle = ':';
        L3_2.linestyle = ':';
    end
    for i=1:2
        set(sbmeasures(i),'enable','off')
    end
    set(order1,'enable','off')

%---------------------------------------------------------------------
% fdellip('clean')
% opposite of 'dirty'
case 'clean'
    if Lresp.linestyle ~= '-'
        Lresp.linestyle = '-';
        L1.linestyle = '-';
        L2.linestyle = '-';
        L3_1.linestyle = '-';
        L3_2.linestyle = '-';
    end
    for i=1:2
        set(sbmeasures(i),'enable','on')
    end
    set(order1,'enable','on')
    filtdes('setenable','off')
    
%---------------------------------------------------------------------
% fdellip('fchange',i)
%    Callback when frequency i has changed
%    Need to update ranges and lines L1, L2
case 'fchange'
    type = bandpop.value;
    if nargin == 1
    % a passband freq spec has changed  (we are in set mode)
        if type >= 3
            Fpass = [Fp1.value Fp2.value];
            if Fpass(1) >= Fpass(2)
                FpassOld = [L3_1.xdata(1) L3_2.xdata(1)];
                i = find(Fpass~=FpassOld);  % index of changed band edge
                if i == 1
                    Fpass(2) = (Fpass(1)+Fs/2)/2;
                    set(Fp2,'value',Fpass(2))
                else
                    Fpass(1) = Fpass(2)/2;
                    set(Fp1,'value',Fpass(1))
                end
            end
            set(L3_1,'xdata',Fpass([1 1]))
            set(L3_2,'xdata',Fpass([2 2]))
        else
            Fpass = Fp1.value;
            set(L3_1,'xdata',Fpass([1 1]))
        end
        
        fdellip('dirty')
        return
    end
    i = varargin{2};
    xd1 = L1.xdata;
    xd2 = L2.xdata;
    f = [f1.value,f2.value,f3.value,f4.value];
    % update lines
    switch type
    case 1
      % L1 xdata = [0 f1 NaN 0 f1]
      % L2 xdata = [f2 Fs/2]
        if i==1
            xd1([2 5]) = f(1);
        else
            xd2(1) = f(2);
        end
    case 2
      % L1 xdata = [f2 Fs/2 NaN f2 Fs/2]
      % L2 xdata = [0 f1]
        if i == 1
            xd2(2) = f(1);
        else
            xd1([1 4]) = f(2);
        end
    case 3  % bandpass
      % L1 xdata = [f2 f3 NaN f2 f3]
      % L2 xdata = [0 f1 NaN f4 Fs/2]
        if xd2(2) ~= f(1)
            xd2(2) = f(1);
        elseif xd1(1) ~= f(2)
            xd1([1 4]) = f(2);
        elseif xd1(2) ~= f(3)
            xd1([2 5]) = f(3);
        elseif xd2(4) ~= f(4)
            xd2(4) = f(4);
        end
    case 4
      % L1 xdata = [0 f1 NaN 0 f1 NaN f4 Fs/2 NaN f4 Fs/2]
      % L2 xdata = [f2 f3]
        if xd1(2) ~= f(1)
            xd1([2 5]) = f(1);
        elseif xd2(1) ~= f(2)
            xd2(1) = f(2);
        elseif xd2(2) ~= f(3)
            xd2(2) = f(3);
        elseif xd1(7) ~= f(4)
            xd1([7 10]) = f(4);
        end
    end
    
    if ~minOrdCheckbox.value   % set order
        %passbandChange = ...
        %  (type==(1:4))*[1 0 0 0; 0 1 0 0;...
        %         0 1 1 0; 1 0 0 1 ]*(i==(1:4))';
        %if passbandChange
        %    fChangeMeas(i,type,Fs,Lresp,L1,L2,f1,f2,f3,f4,Rp,Rs,Fp1,Fp2)
        %    return
        %end
        L3_1.xdata = Fp1.value([1 1]);
        if type>2
            L3_2.xdata = Fp2.value([1 1]);
        end
    else
        [xd1,xd2] = fdutil('validateBands',xd1,xd2,...
                           type,i,f,f1,f2,f3,f4,Fs);
    end

    dirty = 0; % Flag used to indicate that specs have changed.
    
    % If there's a NaN in the data being compared the if-statement will
    % fail (return false) even tough the two variables are equal.  So,
    % remove the NaNs before comparing.
    nonNaNindx_L1 = ~isnan(L1.xdata);
    nonNaNindx_xd1 = ~isnan(xd1);
    if ~isequal(xd1(nonNaNindx_xd1),L1.xdata(nonNaNindx_L1)) 
        % only set if changed
        L1.xdata = xd1;
        dirty = 1;
    end

    % If there's a NaN in the data being compared the if-statement will
    % fail (return false) even tough the two variables are equal.  So,
    % remove the NaNs before comparing.
    nonNaNindx_L2 = ~isnan(L2.xdata);
    nonNaNindx_xd2 = ~isnan(xd2);
    if ~isequal(xd2(nonNaNindx_xd2),L2.xdata(nonNaNindx_L2)) 
        % only set if changed
        L2.xdata = xd2;
        dirty = 1;
    end

    if dirty  % Specs changed; update passband limits; show dotted lines
        ax.xlimPassband = fdutil('xlimpassband',type,...
                         Fs,f1.value,f2.value,f3.value,f4.value);
        fdellip('dirty')                 
    end
    
%---------------------------------------------------------------------
% fdellip('Rpchange')
%  Callback when Rp has changed
%  Need to update line L1
case 'Rpchange'
    type = bandpop.value;
    Rpass = Rp.value;
    above = 0; below = -Rpass;
    
    if type ~= 4
    % 'ydata':[maxpass maxpass NaN minpass minpass]
        yd = [above above NaN below below];
    else
    % 'ydata': [ maxpass maxpass NaN minpass minpass NaN ...
    %                    maxpass maxpass NaN minpass minpass])
        yd = [above above NaN below below ...
               above above NaN below below ];
    end
    L1.ydata = yd;
    ylim = [below above];
    dyl = (ylim(2)-ylim(1))*.15;
    
    ax.ylimPassband = ylim + [-dyl/2 dyl/2];
    
    fdellip('dirty')

    
%---------------------------------------------------------------------
% fdellip('Rschange')
%  Callback when Rs has changed
%  Need to update line L2
case 'Rschange'
    type = bandpop.value;
    
    Rstop = Rs.value;
    if type ~= 3
        yd = [-Rstop -Rstop];
    else
        yd = [-Rstop -Rstop NaN -Rstop -Rstop];
    end
    L2.ydata = yd;
    fdellip('dirty')

%---------------------------------------------------------------------
% fdellip('checkbox')
%  Callback of minimum order checkbox
case 'checkbox'
    filt = filtdes('filt');
    
    newSetOrderFlag = ~get(minOrdCheckbox,'value');
    type = bandpop.value;
    oldtype = filt.specs.fdellip.type;
    if ~newSetOrderFlag   % from set to estimate order 
        if filt.specs.fdellip.setOrderFlag
            % obtain frequencies from measurements
            c = {pbspecs(1) pbspecs(2) sbmeasures(1) sbmeasures(2)};
            if (type==2) | (type==3)
                ind = [3 1 2 4];
            else
                ind = [1 3 4 2];
            end
            f = getFrequencyValues(oldtype,c{ind},Fs);
        else
            % obtain frequencies from filter specs field
            f = filt.specs.fdellip.f;
        end
        f = filt.specs.fdellip.f;
        f = [0; fdutil('changeFilterType',type,oldtype,sort(f(2:end-1))); 1];
        Fpass = [0 0];  % place holder - ignored by 'newfilt'     
    else   % from estimate to set order 
        Fpass = Fp1.value * 2/Fs;
        if type > 2
            if oldtype > 2
                Fpass(2) = Fp2.value * 2/Fs;
            else
                Fpass(2) = (Fpass(1)+1)/2;
            end
        end
        f = [];  % place holder - ignored by 'newfilt'
    end
    
    fdellip('newfilt',newSetOrderFlag,...
                       type,f,Rp.value,...
                       Rs.value,Fpass,order.value)
    fdellip('dirty')

%---------------------------------------------------------------------
% fdellip('newfilt',setOrderFlag,type,f,Rp,Rs,Fpass,order)
%  set values of SPECIFICATIONS objects ...  DOES NOT DESIGN FILTER
case 'newfilt'
    setOrderFlag = varargin{2};
    type = varargin{3};
    f = varargin{4};     % in range (0,1)
    Rpass = varargin{5};
    Rstop = varargin{6};
    Fpass = varargin{7};  % in range (0,1)
    N = varargin{8};
    
    bandpop.value = type;
    % save last value of bandpop in passframe userdata:
    passframe.userdata = type;
    minOrdCheckbox.value = ~setOrderFlag;

    if ~setOrderFlag  % estimate order
        % initialize specs:
        order = order1;
        set(order0,'visible','off')

        [f1,f2,f3,f4] = setupFrequencyObjects(type,'fdellip',...
                           pbspecs,sbspecs,f,Fs,ax);
        
        pbspecs(1).visible = 'on';
        pbspecs(3).visible = 'on';
        sbspecs(1).visible = 'on';
        sbspecs(3).visible = 'on';
                
        Rp = pbspecs(3);
        Rs = sbspecs(3);
        set(Rp,'value',Rpass)
        set(Rs,'value',Rstop)
        set(L3_1,'visible','off')
        set(L3_2,'visible','off')
    else  % set order
        order = order0;
        set(order0,'visible','on')
                        
        set(sbspecs(1),'visible','off')
        set(sbspecs(2),'visible','off')
        
        set(L3_1,'visible','on','xdata',Fpass([1 1])*Fs/2)     
        if type < 3  % low/high
            set(Fp1,'value',Fpass(1)*Fs/2,'range',[0 1]*Fs/2,...
               'label','Fp','callback','fdellip(''fchange'')',...
               'visible','on')
            Fp2.visible = 'off';
            set(L3_2,'visible','off')
        else  % pass/stop
            set(Fp1,'value',Fpass(1)*Fs/2,'range',[0 Fpass(2)]*Fs/2,...
               'label','Fp1','callback','fdellip(''fchange'')',...
               'visible','on')
            set(Fp2,'value',Fpass(2)*Fs/2,'range',[Fpass(1) 1]*Fs/2,...
               'label','Fp2','callback','fdellip(''fchange'')',...
               'visible','on')
            set(L3_2,'visible','on','xdata',Fpass([2 2])*Fs/2)     
        end
        order.value = N;
    end

    if ax.xlimbound(2) ~= Fs/2
        set(ax,'xlimbound',[0 Fs/2],'xlim',[0 Fs/2])
    end
    
    if ~setOrderFlag  % estimate order
        minpass = -Rpass;
        maxpass = 0;
        minstop = -Rstop;
        fdutil('setLines','fdellip',L1,L2,setOrderFlag,...
                          type,f(:)',Fs,minpass,maxpass,minstop)
    else  % set order
        set(L1,'segmentdragmode',{'none'},...
               'segmentpointer',{'forbidden'},...
               'vertexdragmode',{'none'},...
               'vertexpointer',{'forbidden'})
    end
    
%---------------------------------------------------------------------
% fdellip('newtype')
%  callback of band configuration popup
case 'newtype'
    filt = filtdes('filt');
    newtype = bandpop.value;
    oldtype = get(passframe,'userdata');
    if isempty(oldtype)
        oldtype = filt.specs.fdellip.type;
    end
    passframe.userdata = newtype;
    
    if (newtype ~= oldtype) | strcmp(filtdes('getenable'),'on')
        if ~minOrdCheckbox.value
            Fpass = Fp1.value * 2/Fs;
            if newtype > 2
                Fpass(2) = Fp2.value * 2/Fs;
                if Fpass(2) <= Fpass(1) | Fpass(2)>1
                    Fpass(2) = (Fpass(1) + 1)/2;
                    Fp2.value = Fpass(2)*Fs/2;
                end
            end
            f = [];
        else
            if oldtype < 3  % low or high pass
                edges = [f1.value f2.value]'*2/Fs;
            else
                edges = [f1.value f2.value f3.value f4.value]'*2/Fs;
            end
            edges = fdutil('changeFilterType',newtype,oldtype,edges);
            f = [0; edges(:); 1];
            Fpass = [0 0]; % place holder - ignored by newfilt
        end
        
        fdellip('newfilt',~minOrdCheckbox.value,newtype,f,Rp.value,...
                  Rs.value,Fpass,order.value)
        fdellip('dirty')
        
    else
       % disp('no change of type')
    end
    
%---------------------------------------------------------------------
% fdellip('Lrespdown')
%  Button down fcn of Lresp (response line) - pan
case 'LrespDown'
    bounds.xlim = [0 Fs/2];
    bounds.ylim = [-500 30];
    h = ax.h;
    panfcn('Ax',h,...
           'Bounds',bounds,...
           'UserHand',get(h,'zlabel'),...
           'Invisible',[L3_1.h L3_2.h])
           
%---------------------------------------------------------------------
% fdellip('L1down')
%  Button down fcn of L1
% fdellip('L2down')
%  Button down fcn of L2
% fdellip('L3_down',i)
%   buttondown fcn of stopband edge line 1 or 2 (i==1 or 2)
case {'L1down', 'L2down', 'L3_down'}

    % NO OP
%---------------------------------------------------------------------
% fdellip('L1up')
%  Button up fcn of L1
% fdellip('L2up')
%  Button up fcn of L2
case {'L1up', 'L2up'}

    % NO OP
%---------------------------------------------------------------------
% fdellip('L3_drag',ind)
%  segment drag callback of L3_1 and L3_2 - stopband edge frequency lines
%  Inputs:
%     ind - index of line being dragged, 1 or 2
case 'L3_drag'
    ind = varargin{2};
    minspacing = Fs/500;
    if ind == 1
        xd = L3_1.xdata;
        newFpass1 = inbounds(xd(1),[minspacing Fp1.range(2)-minspacing]);
        if newFpass1 ~= Fp1.value
            Fp1.value = newFpass1;
            Fp2.range = [newFpass1 Fs/2];
            if newFpass1 ~= xd(1)
                L3_1.xdata = newFpass1([1 1]);
            end
        end
    else
        xd = L3_2.xdata;
        newFpass2 = inbounds(xd(1),[Fp2.range(1)+minspacing Fs/2-minspacing]);
        if newFpass2 ~= Fp2.value
            Fp2.value = newFpass2;
            Fp1.range = [0 newFpass2];
            if newFpass2 ~= xd(1)
                L3_2.xdata = newFpass2([1 1]);
            end
        end
    end

%---------------------------------------------------------------------
% fdellip('L1drag',type,ind)
%  vertex drag callback of L1 - passband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of vertex being dragged
case 'L1drag'
    type = varargin{2};
    ind = varargin{3};
    xd = L1.xdata;
    minspacing = Fs/500;
    switch type
    case 1  % lowpass
        newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
        xd([2 5]) = newf1;
        L1.xdata = xd;
        f1.value = newf1;
        i = 1;
    case 2  % highpass
        newf2 = inbounds(xd(ind),[f1.value+minspacing Fs/2-minspacing]);
        xd([1 4]) = newf2;
        L1.xdata = xd;
        f2.value = newf2;
        i = 2;
    case 3  % bandpass
    % L1 xdata = [f2 f3 NaN f2 f3]
        if any(ind == [1 4])   % dragging f2
            newf2 = inbounds(xd(ind),[f1.value+minspacing f3.value-minspacing]);
            xd([1 4]) = newf2;
            L1.xdata = xd;
            f2.value = newf2;
            i = 2;
        else % dragging f3
            newf3 = inbounds(xd(ind),[f2.value+minspacing f4.value-minspacing]);
            xd([2 5]) = newf3;
            L1.xdata = xd;
            f3.value = newf3;
            i = 3;
        end
    case 4   % bandstop
    % L1 xdata = [0 f1 NaN 0 f1 NaN f4 Fs/2 NaN f4 Fs/2]
        if any(ind == [2 5])   % dragging f1
            newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
            xd([2 5]) = newf1;
            L1.xdata = xd;
            f1.value = newf1;
            i = 1;
        else % dragging f4
            newf4 = inbounds(xd(ind),[f3.value+minspacing Fs/2-minspacing]);
            xd([7 10]) = newf4;
            L1.xdata = xd;
            f4.value = newf4;
            i = 4;
        end
    end
    ax.xlimPassband = fdutil('xlimpassband',type,...
                         Fs,f1.value,f2.value,f3.value,f4.value);

%---------------------------------------------------------------------
% fdellip('L2drag',type,ind)
%  drag callback of L2 - stopband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of vertex being dragged
case 'L2drag'
    type = varargin{2};
    ind = varargin{3};
    xd = L2.xdata;
    minspacing = Fs/500;
    switch type
    case 1  % lowpass
        newf2 = inbounds(xd(ind),[f1.value+minspacing Fs/2-minspacing]);
        xd(1) = newf2;
        L2.xdata = xd;
        f2.value = newf2;
        i = 2;
    case 2  % highpass
        newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
        xd(2) = newf1;
        L2.xdata = xd;
        f1.value = newf1;
        i = 1;
    case 3  % bandpass
    % L2 xdata = [0 f1 NaN f4 Fs/2]
        if ind == 2   % dragging f1
            newf1 = inbounds(xd(ind),[minspacing f2.value-minspacing]);
            xd(2) = newf1;
            L2.xdata = xd;
            f1.value = newf1;
            i = 1;
        else % dragging f4
            newf4 = inbounds(xd(ind),[f3.value+minspacing Fs/2-minspacing]);
            xd(4) = newf4;
            L2.xdata = xd;
            f4.value = newf4;
            i = 4;
        end
    case 4   % bandstop
    % L2 xdata = [f2 f3]
        if ind == 1   % dragging f2
            newf2 = inbounds(xd(ind),[f1.value+minspacing f3.value-minspacing]);
            xd(1) = newf2;
            L2.xdata = xd;
            f2.value = newf2;
            i = 2;
        else % dragging f3
            newf3 = inbounds(xd(ind),[f2.value+minspacing f4.value-minspacing]);
            xd(2) = newf3;
            L2.xdata = xd;
            f3.value = newf3;
            i = 3;
        end
    end
    
%---------------------------------------------------------------------
% fdellip('Rpdrag',type,ind)
%  drag callback of L1 - passband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of segment being dragged
case 'Rpdrag'
    type = varargin{2};
    ind = varargin{3};
    yd = L1.ydata;
    
    below = yd(ind);
    if below >= 0 
        below = -.00001;
    elseif below < -10
        below = -10;
    end
    above = 0;
    
    newRp = above-below;

    if type ~= 4
    % 'ydata':[maxpass maxpass NaN minpass minpass]
        yd = [above above NaN below below];
    else
    % 'ydata': [ maxpass maxpass NaN minpass minpass NaN ...
    %                    maxpass maxpass NaN minpass minpass])
        yd = [above above NaN below below ...
               NaN above above NaN below below ];
    end
    L1.ydata = yd;
    Rp.value = newRp;
    ylim = [below above];
    dyl = (ylim(2)-ylim(1))*.15;
    ax.ylimPassband = ylim + [-dyl/2 dyl/2];
 
%---------------------------------------------------------------------
% fdellip('Rsdrag',type,ind)
%  drag callback of L2 - stopband line
%  Inputs:
%     type - band configuration 1==low, 2=high, 3=pass, 4=stop
%     ind - index of segment being dragged
case 'Rsdrag'
    type = varargin{2};
    ind = varargin{3};
  
    yd = L2.ydata;
    newRs = -yd(ind);
    if newRs < 0
        newRs = 0;
    end
    switch type
    case {1,2,4}
        L2.ydata = [-newRs -newRs];
    case 3
        L2.ydata = [-newRs -newRs NaN -newRs -newRs];
    end
    set(Rs,'value', newRs)
    
end  % of function switch-yard

%---------------------------------------------------------------------
% -------- LOCAL FUNCTIONS START HERE  --------- 
%---------------------------------------------------------------------

function sethelp
global minOrdCheckbox bandpop 
global passframe stopframe passframe1 stopframe1
global f1 f2 f3 f4 Fp1 Fp2 order Rp Rm pbspecs sbspecs
global Fs1m Fs2m
global ax L1 L2 Lresp
global Fs

% disp('setting help ... stub')

function [n,Fpass] = estimateOrder(type,Rp,Rs,Fs,f1,f2,f3,f4)
% [n,Fpass] = estimateOrder(type,Rp,Rs,Fs,f1,f2,f3,f4)
%   estimate filter order
%   takes the specifications as given by the input
%   parameters and estimates the order and stopband edge frequencies
%   needed to meet those specifications.
% Inputs:
%  type - 1,2,3,4 specifies band configuration
%  Rp, Rs passband, stopband ripple
%  Fs - sampling frequency
%  f1,f2  first two frequencies in ascending order
%  f3,f4 only needed if type == 3 or 4, remaining frequencies
%    f1,f2,f3,f4 are assumed between 0 and Fs/2 on input
% Outputs:
%  n - filter order
%  Fpass - filter pass band edges for ellip, normalized to range [0...1]

if type == 1    % low pass
    Wp = f1;   Ws = f2;
elseif type == 2   % high pass
    Wp = f2;   Ws = f1;
elseif type == 3   % band pass
    Wp = [f2 f3];   Ws = [f1 f4];
elseif type == 4   % band stop
    Wp = [f1 f4];   Ws = [f2 f3];
end
[n,Fpass] = ellipord(Wp*2/Fs,Ws*2/Fs,Rp,Rs);
Fpass = Fpass(:)';   % make it a row 
 

function yd = passbandlimits(Rp)
% return ydata = [minpass maxpass] of passband 
%   given Rp decibels of ripple in passband (with maximum 1 in linear scale)
    above = 0; below = -Rp;
    yd = [below above];


function [maxpass,minpass,minstop] = getMagMeasurements(ff,Hlog,type,...
                                          f1,f2,f3,f4);
%getMagMeasurements
% Finds passband and stopband ripple for given band edges 
% given a filter's magnitude response
% Inputs:
%  ff - xdata of response
%  Hlog - magnitude of response at frequencies ff, in dB
%  type - band configuration (lp = 1, hp = 2, bp = 3, bs = 4)
%  f1, f2, f3, f4 - band edges (f3 and f4 ignored if type < 3)
%           in same units as ff
% Output:
%  fm - 2 or 4 element frequency vector in ascending order
    switch type
    case 1   % lowpass
        passInd = find(ff<=f1);
        stopInd = find(ff>=f2);
    case 2   % highpass
        stopInd = find(ff<=f1);
        passInd = find(ff>=f2);
    case 3   % bandpass
        stopInd = find((ff<=f1)|(ff>=f4));
        passInd = find((ff>=f2)&(ff<=f3));
    case 4   % bandstop
        passInd = find((ff<=f1)|(ff>=f4));
        stopInd = find((ff>=f2)&(ff<=f3));
    end
    maxpass = max(Hlog(passInd));
    minpass = min(Hlog(passInd));
    minstop = max(Hlog(stopInd));

function Fstop = getFreqMeasurements(ff,Hlog,type,Rp,Rs,Fpass)
%getFreqMeasurements
% Finds stop band edges for elliptic filter given passband and 
% stopband ripple and given a filter's magnitude response
% Inputs:
%  ff - xdata of response (assumed a column vector)
%  Hlog - magnitude of response at frequencies ff, in dB
%               (assumed a column vector)
%  type - band configuration (lp = 1, hp = 2, bp = 3, bs = 4)
%  Rp - passband ripple, in dB
%  Rs - stopband attenuation in dB
%  Fpass - passband edges, normalized to [0 Fs/2]
% Output:
%  Fstop - 1 or 2 element frequency (column) vector in ascending order
    ff = ff(:);
    switch type
    case 1   % lowpass
        stopInd = find(Hlog(:)<=-Rs);
        Fstop = ff(stopInd(1));
    case 2   % highpass
        stopInd = find(Hlog(:)<=-Rs);
        Fstop = ff(stopInd(end));
        %passInd = find(Hlog(:)>-Rs);
        %Fstop = ff(passInd(1)-1);
    case 3   % bandpass
        passInd = find(Hlog(:)>=-Rp);
        stopInd1 = find(Hlog(passInd(1):-1:1)<=-Rs);
        stopInd2 = find(Hlog(passInd(end):end)<=-Rs);
        Fstop = ff([passInd(1)-stopInd1(1) passInd(end)+stopInd2(1)]);
    case 4   % bandstop
        stopInd = find(Hlog(:)<=-Rs);
        Fstop = ff(stopInd([1 end]));
    end
    
    
function updateLines(passbandChange,type,fchange_ind,f1,f2,f3,f4,Rp,Rs,Fs)
% assume values of f1,f2,f3,f4,Rp and Rs are correct now
% fchange_ind - vector of indices indicating which frequencies have
%               changed
    global L1 L2 ax
    
    f = getFrequencyValues(type,f1,f2,f3,f4,Fs)*Fs/2;
    
    if any(passbandChange==1)
        maxpass = 0;
        minpass = -Rp.value;
        % update L1 xdata and ydata
        switch type
        case 1   % lowpass
            set(L1,'xdata',[f(1:2) NaN f(1:2)],...
                   'ydata',[maxpass maxpass NaN minpass minpass])
        case 2   % highpass
            set(L1,'xdata',[f(3:4) NaN f(3:4)],...
                   'ydata',[maxpass maxpass NaN minpass minpass ])
        case 3   % bandpass
            set(L1,'xdata',[f(3:4) NaN f(3:4)],...
                   'ydata',[maxpass maxpass NaN minpass minpass])
        case 4   % bandstop
            set(L1,'xdata',[f(1:2) NaN f(1:2) NaN f(5:6) NaN f(5:6)],...
                   'ydata',[ maxpass maxpass NaN minpass minpass NaN ...
                             maxpass maxpass NaN minpass minpass])
        end
        ylim = [minpass maxpass];
        dyl = (ylim(2)-ylim(1))*.15;
        ax.ylimPassband = ylim + [-dyl/2 dyl/2];
        if length(f)==4
            f(6)=0;  % zeropad for call to xlimpassband
        end
        ax.xlimPassband = fdutil('xlimpassband',type,...
                             Fs,f(2),f(3),f(4),f(5));
    end
    if any(passbandChange==0)
        minstop = -Rs.value;
        % update L2 xdata and ydata
        switch type
        case 1   % lowpass
            set(L2,'xdata',[f(3:4)],'ydata',[minstop minstop])
        case 2   % highpass
            set(L2,'xdata',[f(1:2)],'ydata',[ minstop minstop])
        case 3   % bandpass
            set(L2,'xdata',[f(1:2) NaN f(5:6)],...
                   'ydata',[ minstop minstop NaN minstop minstop])
        case 4   % bandstop
            set(L2,'xdata',[f(3:4)],'ydata',[minstop minstop])
        end
    end
    %fdutil('updateRanges',fchange_ind,f1,f2,f3,f4)
    set(f1,'range',[0 Fs/2])
    set(f2,'range',[0 Fs/2])
    set(f3,'range',[0 Fs/2])
    set(f4,'range',[0 Fs/2])
    
function [f1,f2,f3,f4] = setupFrequencyObjects(type,module,pbobjects,...
                   sbobjects,f,Fs,ax,setValueFlag)

    if nargin<8
        setValueFlag = 1;
    end
    
    switch type
    case 1 % lowpass
        f1 = pbobjects(1);
        f2 = sbobjects(1);
        f3 = sbobjects(2);
        f4 = pbobjects(2);
        pbobjects(2).visible = 'off';
        sbobjects(2).visible = 'off';
        set(f1,'label','Fp')
        set(f2,'label','Fs')
    case 2 % highpass
        f1 = sbobjects(1);
        f2 = pbobjects(1);
        f3 = pbobjects(2);
        f4 = sbobjects(2);
        pbobjects(2).visible = 'off';
        sbobjects(2).visible = 'off';
        set(f1,'label','Fs')
        set(f2,'label','Fp')
    case 3 % bandpass
        f1 = sbobjects(1);
        f2 = pbobjects(1);
        f3 = pbobjects(2);
        f4 = sbobjects(2);
        pbobjects(2).visible = 'on';
        sbobjects(2).visible = 'on';
        set(f1,'label','Fs1')
        set(f2,'label','Fp1')
        set(f3,'label','Fp2')
        set(f4,'label','Fs2')
    case 4
        f1 = pbobjects(1);
        f2 = sbobjects(1);
        f3 = sbobjects(2);
        f4 = pbobjects(2);
        pbobjects(2).visible = 'on';
        sbobjects(2).visible = 'on';
        set(f1,'label','Fp1')
        set(f2,'label','Fs1')
        set(f3,'label','Fs2')
        set(f4,'label','Fp2')
    end
    if setValueFlag
        if type < 3
            set(f1,'value',f(2)*Fs/2,'range',[0 f(3)]*Fs/2)
            set(f2,'value',f(3)*Fs/2,'range',[f(2) 1]*Fs/2)
        else
            set(f1,'value',f(2)*Fs/2,'range',[0 f(3)*Fs/2])
            set(f2,'value',f(3)*Fs/2,'range',[f(2) f(4)]*Fs/2)
            set(f3,'value',f(4)*Fs/2,'range',[f(3) f(5)]*Fs/2)
            set(f4,'value',f(5)*Fs/2,'range',[f(4) 1]*Fs/2)
        end
        ax.xlimPassband = fdutil('xlimpassband',type,...
                             Fs,f1.value,f2.value,f3.value,f4.value);
    end
    set(f1,'range',[0 Fs/2])
    set(f2,'range',[0 Fs/2])
    set(f3,'range',[0 Fs/2])
    set(f4,'range',[0 Fs/2])
    
    f1.callback = [module '(''fchange'',1)'];
    f2.callback = [module '(''fchange'',2)'];
    f3.callback = [module '(''fchange'',3)'];
    f4.callback = [module '(''fchange'',4)'];
        

function setupMeasurementObjects(specStruc,Fstop,Fs,...
                  order1,sbmeasures,Fs1m,Fs2m)
%  set values of MEASUREMENTS objects ... assumes specStruct is current

    setOrderFlag = specStruc.setOrderFlag;
    type = specStruc.type;
    N = specStruc.order;
    
    set(Fs1m,'value',Fstop(1),'format','%1.4g')
    if type > 2
        set(Fs1m,'label','Actual Fs1')
        set(Fs2m,'visible','on','value',Fstop(2),...
            'format','%1.4g','label','Actual Fs2')
    else
        set(Fs1m,'label','Actual Fs')
        set(Fs2m,'visible','off')
    end
    
    if ~setOrderFlag  % estimate order
        set(order1,'visible','on')
        order1.value = N;
    else
        set(order1,'visible','off')
    end
    for i=1:2
        set(sbmeasures(i),'enable','on')
    end
    set(order1,'enable','on')


function specStruc = measureFilt(objSetupFlag,specStruc,Fs,order1,...
                  sbmeasures,Fs1m,Fs2m,ff,Hlog,L1,L2,ax)

    n = specStruc.order;    
    setOrderFlag = specStruc.setOrderFlag;
    Fpass = specStruc.Fpass*Fs/2;
    
    Fstop = getFreqMeasurements(ff,Hlog,specStruc.type,...
                             specStruc.Rp,specStruc.Rs,Fpass);
    if objSetupFlag
        setupMeasurementObjects(specStruc,Fstop,Fs,...
                  order1,sbmeasures,Fs1m,Fs2m)    
    else
        set(Fs1m,'value',Fstop(1))
        if specStruc.type > 2
            set(Fs2m,'value',Fstop(2))
        end
        if ~setOrderFlag
            order1.value = n;
        end
    end

    if setOrderFlag
        % Update stopband edges in specStruc frequency vector:
        switch specStruc.type
        case 1
            f = [0 Fpass Fstop Fs/2];
        case 2
            f = [0 Fstop Fpass Fs/2];
        case 3
            f = [0 Fstop(1) Fpass(:)' Fstop(2) Fs/2];
        case 4
            f = [0 Fpass(1) Fstop(:)' Fpass(2) Fs/2];
        end
        specStruc.f = f*2/Fs;
    else
        f = specStruc.f*Fs/2;
    end
    
    maxpass = 0;   minpass = -specStruc.Rp;   minstop = -specStruc.Rs;
    
    % update L1 and L2 xdata and ydata, pointers, dragmodes
    fdutil('setLines','fdellip',L1,L2,specStruc.setOrderFlag,...
                      specStruc.type,specStruc.f(:)',...
                       Fs,minpass,maxpass,minstop)

    % update [ylim/xlim] passband limits
    ylim = [minpass maxpass];
    dyl = (ylim(2)-ylim(1))*.15;
    set(ax,'ylimPassband',ylim + [-dyl/2 dyl/2]);
    ax.xlimPassband = fdutil('xlimpassband',specStruc.type,...
                              Fs,f(2),f(3),f(end-2),f(end-1));

function f = getFrequencyValues(type,f1,f2,f3,f4,Fs);            
if type < 3  % low or high pass
    f = [0 f1.value f2.value Fs/2]*2/Fs;
else
    f = [0 f1.value f2.value f3.value f4.value Fs/2]*2/Fs;
end

function [setOrderFlag_init, type_init, f_init, Rp_init, Rs_init, ...
         order_init, Fpass_init] = initSpecs(filt)
%initSpecs   Initial specifications for ellip filter, from
%            filt input
%Switches off of filt.currentModule and if it finds any of
% fdcheby1, fdbutter, fdcheby2, fdremez, fdfirls, or fdkaiser
% retains the type, order, band edge, and any other relevant
% parameters

    % first define default values
    setOrderFlag_init = 0;   % by default, estimate order 
    type_init = 1;  % 1=lowpass, 2=highpass, 3=bandpass, 4=bandstop
    f_init = [0 .1 .15 1];
    Rp_init = 3;
    Rs_init = 20;
    order_init = 30;
    Fpass_init = .22;
    if strcmp(filt.specs.currentModule,'fdpzedit')
        if isfield(filt.specs.fdpzedit,'oldModule')
            filt.specs.currentModule = filt.specs.fdpzedit.oldModule;
        end
    end
    switch filt.specs.currentModule
    case {'fdcheby1','fdbutter','fdcheby2','fdremez','fdkaiser','fdfirls'}
        s = eval(['filt.specs.' filt.specs.currentModule]);
        setOrderFlag_init = s.setOrderFlag;
        type_init = s.type;
        f_init = s.f;
        Rp_init = s.Rp;
        Rs_init = s.Rs;
        order_init = s.order;
        switch filt.specs.currentModule
        case 'fdcheby1'
            Fpass_init = s.Fpass;
        case 'fdbutter'
            Fpass_init = s.w3db;
        case 'fdcheby2'
            Fpass_init = s.Fstop;
        case {'fdremez','fdfirls'}
            switch s.type
            case {1,2}
                Fpass_init = s.f(3);
            case 3
                Fpass_init = s.f([2 5]);
            case 4
                Fpass_init = s.f(3:4);
            end
        case 'fdkaiser'
            Fpass_init = s.Wn;
        end
        if any(strcmp(filt.specs.currentModule,...
                 {'fdremez','fdkaiser','fdfirls'}))
            order_init = ceil(order_init/10); 
             %  FIR filters are much higher order than IIR
        end
    case 'fdellip'
        if isfield(filt.specs,'fdellip')
            setOrderFlag_init = filt.specs.fdellip.setOrderFlag;
            type_init = filt.specs.fdellip.type;
            f_init = filt.specs.fdellip.f;
            Rp_init = filt.specs.fdellip.Rp;
            Rs_init = filt.specs.fdellip.Rs;
            order_init = filt.specs.fdellip.order;
            Fpass_init = filt.specs.fdellip.Fpass;
        end
    end
    
